In recent years, techniques for fabricating microscopic structures have been expected to be applicable to a wide variety of fields. In particular, structural bodies that include structures of nanometer size (so-called nanomaterials) exhibit different optical, electrical and magnetic properties from their corresponding bulk materials, and are therefore attracting enormous interest, both from the fundamental research perspective and the applied research perspective. For example, nanomaterials having a hollow three dimensional structure such as a cylindrical shape are expected to have important roles in a variety of different fields, including inclusion chemistry, electrochemistry, materials science, biomedicine, sensors, catalysts and separation techniques. Furthermore, techniques for fabricating line-shaped micropatterns can be linked directly to the fabrication of integrated circuits and increased integration levels, and are therefore the subject of extremely intensive research and development in fields such as the semiconductor industry.
As a method of fabricating microscopic structures, a method using lithography method is known. However, in a photo/electron beam lithography method, a large number of processes such as formation of a metal film, patterning and etching are required, which makes the method complicated. Therefore, a method of fabricating a metal structure has been demanded which is more simple with large area and controlled size and shape.
On the other hand, in recent years, a method has been disclosed in which a fine pattern is formed using a phase-separated structure formed from a block copolymer having mutually incompatible polymers bonded together (see Patent Document 1). Also, methods have been reported in which metal nanostructures are produced by a metal deposition method or an electroplating method using a nano pattern formed by utilizing a phase-separated structure as a template.
Among these, as a method of producing a metal nanostructure using a phase separation of a block copolymer and a galvanic displacement reaction, a method is known in which metal ions are captured in micelles formed from a block copolymer to thereby produce a metal nanostructure (see Non-Patent Documents 1 to 3).